Tuberculosis caused by Mycobacterium caprae in a camel (Camelus dromedarius)

Background Animal tuberculosis (TB) is distributed worldwide and has a wide range of wild and domestic reservoirs. Few studies concerning TB in camelids have been published in the last decade, particularly as regards Old World Camelids (OWC), but the increase in reports of TB outbreaks in these species in recent years suggests a high susceptibility to the infection. Case presentation We studied a dromedary camel (Camelus dromedarius) herd (n = 24) in which a Mycobacterium caprae infection was detected. The TB infection was confirmed in one animal at necropsy through the detection of TB lesions, mainly in the abdominal organs, and the subsequent isolation of M. caprae (SB0157 spoligotype). The whole herd was additionally tested using cellular and humoral based diagnostic techniques. The intradermal tuberculin test results were compared with those obtained using P22 ELISA for the detection of specific antibodies against the M. tuberculosis complex. The TB infected animal was a positive reactor to both the intradermal tuberculin tests and P22 ELISA, while the others were negative to all the diagnostic tests. Conclusion The present study found M. caprae infection in OWC. This is the first report of M. caprae infection in an OWC not living in a zoo. Since the animal was born in the herd and fed with goat’s milk, this practice was suspected to be the potential source of TB infection, which was not confirmed in the other animals present in the herd. Moreover, our results highlight that the intradermal tuberculin test and the P22 ELISA could be valuable tools for the diagnosis of TB in OWC.

Study on a supplemental test to improve the detection of bovine tuberculosis in individual animals and herds

Background With a worldwide occurrence, bovine tuberculosis (bTB) is a zoonotic disease that is difficult to control, mainly due to the lack of a diagnostic testing to detect infected animals at all stages. Furthermore, the current standard diagnostic test, the Tuberculin Skin Test (TST), is logistically difficult and time consuming. To address this challenge, the aim of this study was to evaluate the sensitivity and specificity of a multiplex enzyme-linked immunosorbent assay (ELISA) comparing with the TST used for the diagnosis of tuberculosis in cattle in Brazil. The study included 400 Nelore females raised for beef on five farms, in different municipalities in Brazil. The comparative cervical test (CCT) was done and on the day of inoculation of the Purified Protein Derivative (PPD) blood samples were obtained and stored for further analysis of the ELISA IDEXX™ Mycobacterium bovis immunoassay. Results Lack of agreement between CCT and ELISA IDEXX™ was observed. No diagnosis described as positive reactor on the CCT was positive at the ELISA, indicating two false positive reactors and 22 negative reactors by CCT were positive by the ELISA IDEXX™. The ELISA IDEXX™ showed sensitivity significantly higher than the official CCT and no significant differences in specificity was observed. ELISA also detected infected animals and herds undetected by the CCT. The parallel use of CCT and ELISA increased sensitivity and the feasibility bTB screening, thus improving the cleaning of the herds. Conclusions The results obtained here suggest that the ELISA IDEXX™ may be a supplemental test for the detection of Mycobacterium bovis infection in regions without routine testing and slaughter, where the disease generally progresses to more advanced stages and antibody responses are likely to be more prevalent. The results provided evidence to support the validation of the ELISA IDEXX™ as a supplemental test for bTB eradication programs.

SEROPREVALENCE OF EQUINE BRUCELLOSIS: FIRST REPORT IN BANGLADESH

Despite the endemicity of brucellosis, there is no report on the equine brucellosis in Bangladesh. The Rose Bengal Test (RBT) was used to determine the seroprevalence of Brucella antibodies amongst 112 horses from different areas of Bangladesh. The overall seroprevalence of equine brucellosis was 1.79%.The prevalence recorded in Ghatail area was 3.45% and there was no positive reactor in Shakipur and Savar areas. Sex wise prevalence showed that the prevalence was 3.08%in female and 0.00% in male horse. Only the adult (>3 years of old) horses showed the positive RBT reaction (2.35%), whereas young (<3 years of old) horses did not showed positive RBT reaction. The present study reports the first serological prevalence of Brucella infection in horses in Bangladesh. There is need for the inclusion of horses in brucellosis surveillance and control strategies in Bangladesh to safeguard people from high risk.

Screening of Predicted Secreted Antigens from Mycobacterium bovis Reveals the Immunodominance of the ESAT-6 Protein Family

ABSTRACT Results of previous studies utilizing bioinformatic approaches in antigen-mining experiments revealed that secreted proteins are among the most frequently recognized antigens from Mycobacterium bovis. Thus, we hypothesized that the analysis of secreted proteins is likely to reveal additional immunogenic antigens that can be used to increase the specificity of diagnostic tests or be suitable vaccination candidates for mycobacterial infections. To test this hypothesis, 382 pools of overlapping peptides spanning 119 M. bovis secreted and potentially secreted proteins were screened for the ability to stimulate a gamma interferon response in vitro using whole blood from tuberculin-positive reactor (TB reactor) cattle. Of the 119 proteins screened, 70 (59%) induced positive responses in the TB reactor animals to various degrees. Strikingly, all but one of the 15 ESAT-6 proteins tested were recognized by at least 30% of the TB reactor animals, with 12 of the 22 most commonly recognized antigens belonging to this protein family. Further analysis of these data demonstrated that there was no significant difference in immunogenicity between the ESAT-6 proteins that were components of potentially intact ESX secretory systems and those corresponding to additional partial esx loci. Importantly for vaccine design, antigenic epitopes in some highly conserved regions shared by numerous ESAT-6 proteins were identified. However, despite this considerable homology, peptide-mapping experiments also revealed that immunodominant peptides were located in regions of amino acid variability.

The Effect of Calcium on Microbial Aggregation during UASB Reactor Start-Up

The dynamics of granule formation were studied using cells from two bench-scale UASB Reactors. The objective was to elucidate factors which influence formation and maintenance of highly active self-agglomerated microbial biomass. Simultaneous examination of biological and physical parameters was performed during the start-up of a calcium-positive (100 mg/1) reactor and a reactor without added calcium. The influence of carbon nutrients and Ca++ on the cell surface and microbial aggregation was studied. The granules formed in both reactors but were larger in the calcium-positive reactor in which they settled 3-4 times faster. A higher rate of biomass accumulation also was evident in the calcium-positive reactor and this allowed a more frequent increase in the substrate loading rate and earlier development of the granular sludge.

The bentonite flocculation test in the serology of tuberculosis. II. Detection of tuberculosis in cattle

A survey of sera from both healthy and tuberculous cattle was made using bentonite sensitized with human old tuberculin (OT) and with a purified BCG carbohydrate antigen (BCG F1). Nine hundred and ninety-five tuberculin-negative and 141 tuberculin-positive reactor cattle were tested. While 52% of the tuberculin-negative cows gave a positive flocculation test with the OT antigen, only 4% reacted with the BCG F1 antigen. Both the proportion of positive titers and the means of titers showed that, regardless of the antigen with which bentonite is sensitized, there is a significant correlation between increase in bentonite titer and the severity of infection in the tuberculin-positive cows, even though the sera from a number of cows—shown on postmortem to have visible lesions—did not give any titer with either bentonite antigen.